Lock



' 2 Sheets-Sheet 1 M. c. MAXWELL ET AL LOCK v Filed April 22, 1955 Oct27 TORNE y Mrk/6M AT Y Oct. 27, `1936.

' M. C. MAXWELL ET AL LOCK4 Filed April 422, 1955 2 Sheets-Sheet 2 fri 1. ,v

Patented Oct. 27, 1936 osano lLCK Maxwell C. Maxwell, Frank E.vlh'onipson, llharies lledin, and Charles B. lllowatamford, Goran.,

assignors to 'lheJale & 'Formen/iig. Co., Stamford, Conn., a corporationof Connecticut Application April 22, 1933, Serial No. 667,470

2i claims.

This invention relates to pin-tumbler cylinders adapted to resistpicking and attack. It is the object of our invention to design apin-tumbler lock which will have special features embodied 5 therein toresist attack as by drilling or forceful rotation, and which will resistthepicking of the tumblers by a special picking tool.

More particularly, our invention embodies a pin-tumbler lock having aportion 'of .relatively 0 weak cross section, and having mounted in thatsection an armor plate which ls exposed when the head of the plugcovering the weak section is forcefully shorn therefrom as by forcefulro- 1 tation of the plug. Preferably, it is a further the armor platethat it will be impossible to remove it when the vfront head of ltheplughas been shorn, and to so position the'plate that it will cover thatportion of the plug which must be attacked in order to reach the tumblerchambers.

A further feature of the invention embodies the design of a cylinderlock so that the first tumbler in all the locks of a particular seriesof cylinders will be ofexactly the same length,

the' length being so chosen as to prevent substantial movement of apicking tool in the lock. Preferably, it is a feature of the inventionrto so arrange at least one of the rearward tumblers of the lock, thatit will be rather short and will require such substantial movement ofthe picking tool as will be impossible of transmittal without movementof the long locking tumbler to plug locking position.

The drivers of our lock are necked or mushroomed so as to make them morepick resisting than regular types of drivers. As a further feature ofour invention We design the front driver of such cross sectionalstrength as to prevent the shear of the relatively weaker necked ormushrooml tumblers, utilizing the length of the front driver to assureits assuming a locking position ahead of the mushroom drivers uponinsertion of a tool into the plug keyway and attempted forceful rotationof the lock, whereby the long tumbler will relieve the necked ormushroomed tumblers from shearing torque.

It is still a further feature of our 'invention I 50 to design one ofthe drivers so that it has a tapered end portion adapted to align theplug of the cylinder lock with the cylinder itself, so as to prevent theapplication of torque to the remaining tumblers and to force the pluginto initial locked position, if, during any picking opdetailed featureof the invention to so anchorl (ci. 'io-r1) eration, the application oftorque-to the plug is momentarily stopped.

As a further feature of our invention we design the cylinder so that itmay be manufactured of die cast metal with driver bores cast therein and5 serving as guides for drills or punches to form corresponding holes ina brass sleeve which is used as a contact between the cylinder and theusual type of brass tumbler plug to prevent corrosion. '10

Further objects of our invention will appear from the description whichfollows.

In the drawings, Fig. l is. a4 cross section of a preferred embodimentof our invention. Figs.

2, 3 and 4 are sections taken along the lines 2, t, l5 and l of Fig. 1,with Fig. 3 showing a modicationof Fig. 1. Fig. 5 is a section takenalong the lines iiof Fig. 1 showing the usual mushroom driver in plugreleasing position. Fig. 6

is a view along the same section as Fig. 5 show- 2o ing the mushroomdriver acting to lock the plug and cylinder together and in its pickresisting position. Fig. 'l is a view illustrating what normally happenswhen a usual type of tumbler lock is picked. Fig. 8 illustrates themanner in 25 whicnthe cast driver bores serve as guides for v a toolused to form the bore in the brass sleeve in which the usual brass plugof thricylinder lies.

Fig. 9 is a perspective View of the sleeve used in Fig. 8. 30

Referring now more particularly' to the drawings, reference numeral illillustrates a die cast cylinder having formed therein a series of castbores l l which serve as guides for a drill or other tool it (see Fig.8) for forming aligned bores i3 35 in the brass sleeve lll. Preferably,but not necessarily, the brass sleeve it is formed with notches i5, sothat when the cylinder lll is cast, With the sleeve il mounted in themold, the cylindei` will be securely fastened to the sleeve by 40 metalflowing into the grooves l5. Of course, other methods may be utilizedfor securing the sleeve to the cylinder.

At the front end of the cylinder, there is mounted a hardened steelplate it which serves as an armor to prevent access to the drivers by adrill. Cooperating with the armor plate it is a further armor plate ilresting in a grooved portion i8 of thetumbler plug I9. The member ilalso rides in a groove 20 in the cylinder so 50 as to be retained in thecylinder independently of the plug body.l The purpose of this construc-vtion is to prevent the application of shearing stress to the cylinderplug I9 as by a screw driver driven into the front portion of the keyway2i of 55 the plug I9. For instance, should a screw driver or other toolbe driven into the keyway 2l, force-` ful rotation will simply shear thehead of the plug from the remainder of the plug, due to the weakenedsection in which Ithe armor plate I1 rests, leaving an exposure as shownin Fig. 2 with the armor plate I1 preventing further access into theplug. It will be impossible to remove the armor plate I1 because of thegroove 20.

In order to prevent the picking of the lock, We utilize a series ofmushroom drivers 22 best illustrated in Figs. 5 and 6. The heads ofthese drivers cooperate with the grooves 23 in the lsleeve I4,-as shownin Fig. 6, whenever sufficient torque is applied to the plug to rotateit the amount permitted by the peculiar shape of the drivers. Movementof the -drivers into release position of Fig. 5, from the lockedposition of Fig. 6, is then practically impossible. It will be readilyunderstood that these mushroom drivers 22 are rather weak because of thecutting away of a portion of their body, and in order to prevent theirshearing by the application of shearing torque to the plug, the firstpin tumbler of the lock, pin 24, is made of slightly larger section thanthe remaining tumblers, and of hardened stainless steel. In addition,this tumbler 24 and its driver are made to fit very closely within thebore to allow for but little play. Also, first tumbler 24, in additiontot its stronger section, is made considerably longer than the remainingtumblers so that the insertion of a picking tool in the keyway 2I willimmediately move the first tumbler into a locking position. Since thistumbler is designed to permit but very slight rotation of the plug andless than is permitted by the drivers 22 in Fig. 6, it will preventapplication of torque to the mushroom drivers and will prevent shearingof the drivers.

By this association of elements, it is readily seen that We utilize themushroom drivers 22 to prevent picking of the lock, and that to preventthe shearing of these drivers, due to their inherent weak construction,we utilize the front long pin. This pin is immediately forced intolocking position by the insertion of a torque applying tool, and willabsorb the torque due to the fact that it will be immediately placed intorque resisting position while the grooved or mushroom tumblers aredesigned to allow considerable movement of the plug from the position ofFig. 5 to the position of Fig. 6 before they perform their lockingfunction.

Fig. '1 illustrates the manner in'which an ordinary plug may be operatedby a picking tool, by simply applying torque various drivers 25 havebeen forced entirely into the cylinder chamber II while the pins 26 havegradually, one by one, been allowed to move over until they areover-hung by the body 21b immediately adjacent the driver bore II, andthe part 21a of the plug will effectively prevent downward lockingmovement of the driver 25. Those skilled in the art will appreciate thatthe position of Fig. 7 is attained by each pin-tumbler and driver inundetermined sequence by skillful use of apicking tool. Any slightcounter clockwise movement from Fig. '7 will immediately realign thedriver and tumbler bores to interlock the plug and cylinder.

Preferably, to aid in forcing the plug body I9 back into a positionwherein the pin 26 will be aligned with the driver 25 upon thealleviation of torque to the plug I9, we utilize a locking driver 21best illustrated in Figs. 1 and 4. I'his lockto the plug until the ingdriver has a bevelled surface 28 which will cooperate with a bevelledsurface 29 of the plug I9 so as to rotate the plug back into borealigning position immediately when picking torque on the plug I9 isdecreased to a deiinite point. For instance, should picking torque betaken from the plug I9 in the position of Fig. '1, the locking driver 21would immediately act as in Fig. 4 to force the plug in a counterclockwise direction to align the pin 26 with the driver 25 whereupon thedriver would be forced down into the pin chamber to lock the plug to thecylinder. Preferably, the spring 30 used with the locking driver is ofrelatively greater strength than the other springs used in the plug soas to exert considerable pressure.

We prefer to utilize astill further means of forcing the plug I9 backinto aligned position to prevent picking such as shown in Fig. '7, bybevelling the upper portion 3II of the front long pin 24 as shown inFig. 3. Thus, should the pin 24 be forced into an upward position by thepicking tool, it will act through its bevelled head 3|, to force analignment of the plug and cylinder bores whereupon, in-a case such asFig. 7, the plug I9 would be placed once more in locking condition bythe driver 25. Preferably, at least one of the tumblers is of suchslight length that a picking tool capable of operating it into a releaseposition would necessarily actuate the long pin 24 into its locking andaligning position.

While we have shown a particular embodiment of our invention, it shouldbe understood that variations of the same Will readily occur to thoseskilled in the art, and that we do not wish to be limited in our patentmonopoly except as may be required by the state of the prior art.

We claim:

1. In a lock, a cylinder, a key plug, a series of tumblers in said keyplug cooperating with drivers in said cylinder, the first of saidtumblers being of relatively great length to prevent substantial`movement of a picking tool in the plug keyway,

Without moving said tumbler into a locked position, and having a taperedend adapted to enter the cylinder driver bore opposite it even when theplug has been rotated suiiiciently to disalign slightly the tumbler anddriver bores.

2. In a lock, a cylinder and a key plug having aligned driver andtumbler bores, drivers and tumblers in said bores, the first of saidtumblers being of relatively great length to prevent substantialmovement of a picking tool in the plug keyway, without moving saidtumbler into a vlocked position, and having a tapered upper end adaptedto enter the particular driver bore associated therewith even when theplug has been rotated somewhat to disalign the tumbler and driver bores,whereby slight actuation of said pin by a picking tool will act torotate the plug relatively to the cylinder and into driver and tumblerbore alignment.

3. In a cylindei` lock, a cylinder, a key plug, an armor plate coveringa cross sectional part of the key plug and adapted to rotate with saidkey plug, and a retaining groove in said cylinder in which said armorplate is adapted to rest whereby to be maintained against removal evenwhen that part of the plug in front of said plate is destroyed.

4. In a cylinder lock, a cylinder, a key plug having a cutaway portionleaving a relatively weak section, an armor plate adapted to rest insaid cutaway portion and covering a vital cross sectional part of saidplug and adapted to rotate with said key plug, and a retaining groove in2,059,129 Asaid cylinder in which said armor plate is adapted to restwhereby to be maintained against removal even when the plug in front ofsaid plate is destroyed.

5. In a cylinder lock, a cylinder, a key plug having a cutaway portionleaving a relatively weak section, an armor plate adapted to rest insaid cutaway portion, said cylinder having a groove, a portion of saidarmor plate arranged to extend into said groove, said armor plate beingof such configuration and size that if the front of the plug and saidweak section be broken away, said armor plate will not be movable out ofits groove in the cylinder and will remain in` protecting relation tothe remainder of 4the plug.

. 6. In a cylinder lock, a cylinder, a key plug having a cutaway portionleaving a relatively Weak section, an armor and retaining plate adaptedto rest in said cutaway portion 'and to rotate with said plug, saidcylinder having a groove, a portion of said armor plate arranged toextend into said groove, said armor plate being of such coniigurationand size that if the front of the plug and said weak section be brokenaway, said armor plate will not be movable out of its groove in thecylinder and will remain in protecting and retaining relation to theremainder oi the plug.

7. In a cylinder lock, a cylinder, a key plug having a cutaway portionleaving a relatively weak section, an armor. and retaining plate adaptedto rest in said cutaway portion and to be supported by said weaksection, said cylinder having a groove, a portion of said armor platearranged to extend into said groove, said armor plate being of suchconguration and size that if the iront of the plug and said weak sectionare broken away, said armor plate will not be movable out of its groovein the cylinder and will remain in protecting and retaining relation tothe remainder of the plug.

8. In a cylinder lock, a cylinder, a key plug mounted to rotate in theusual plug bore in said cylinder, said plug having a weakened section,said cylinder having a groove in its plug bore in the vertical planeoccupied by said weakened plug section and an opening leading from saidgroove to the outside of said cylinder, and an armor plate insertiblethrough said opening and into the weakened section of said plug.

9. In a cylinder lock, a cylinder, a key plug mounted to rotate in theusual plug bore in said cylinder, said plug having a weakened section,said cylinder having a groove in its plug bore in the vertical planeoccupied by said weakened plug section and an opening leading from saidgroove to the outside of said cylinder, and an armor plate insertiblethrough said opening and into the weakened section of said plug, saidarmor plate having also a portion adapted to ride in the cylindergroove.

iii. In a cylinder lock, a cylinder, a key plug mounted to rotate in theusual plug bore in said cylinder., said plug having a weakened section,said cylinder having 'a groove in its plug bore in the vertical planeoccupied by said weakened plug section and an opening leading from saidgroove into the outside of said cylinder, an armor plate insertiblethrough said opening and into the weakened section of said plug, saidarmor plate being rotatable with said plug and having a portion adaptedto extend into the cylinder groove.

11. In a cylinder lock, a cylinder, a key plug mounted to rotate theusual plug bore in said cylinder, said plug having a weakened section,said cylinder having a groove in its plug bore in the vertical planeoccupied said weakened plug section and an` opening leading from saidgroove to the outside of said cylinder, an armor plate insertiblethrough said opening and into the weakened section of said plug, saidarmor plate'being rotatable with said plug and having a portion adaptedto extend into the cylinder groove wherebyto rotate in 'said groove,said plate being of such conguration relatively to the plug bore andgroove that should the front of the plug and said weakened section becut away, said armor plate will not be movable out yof its groove in thecylinder and will remain in retaining and protecting relation to theremaining portion oi' the plug. y i

12. A cylinder lock comprising a cylinder of cast material. a key plugfor said cylinder operating in a cast bore therein, a relativelynon-corrosive sleeve lining for said cylinder bore in which said plug isadapted to rotate, aligned tumbler chambers in said plug, sleeve,and'cylinder, said cylinder bores being cast therein, said sleeve boresbeing punched or drilled therein in alignment with said cast bores.

13. A cylinder lock comprising a cylinder of cast material, a key plugof cast material for said cylinder and operating in a cast bore therein;a relatively non-corrosive lining for said cylinder bore in which saidplug rotates, aligned tumbler chambers in said plug, sleeve, andcylinder, said sleeve being secured against rotation relatively to saidcylinder by fastening means formed during the casting of said cylinder.

14. A cylinder lock comprising a cylinder, a key plug for said cylinderoperating in said plug bore in said cylinder, and a relativelynon-corrosive sleeve of an internal diameter substantially the diameterof the plug and an external diameter substantially the diameterof thecylinder plug bore, arranged between the plug and cylinder.

15. A cylinder lock comprising a cylinder having a plug bore, a key plugfor said cylinder operating in said plug borein said cylinder, and arelatively non-corrosive sleeve of an internal diameter substantiallythe diameter of the plug and an external diameter substantially thediameter of the cylinder plug bore arranged between the plug andcylinder, and means whereby said sleeve is secured against rotationrelatively to one of the said elements between which itis mounted. I

16. In a cylinder lock, a cylinder, a key plug having a cut-away portionleaving a relatively weak section, an armor plate adapted to be insertedin said cut-away portion and to cover a vital cross sectional part ofsaid plug, said armor plate being retained against endwise or rotarymovement relatively to the plug so as to rotate with the plug when saidplug is released for rotation, a retaining groove in said cylinder invwhich a porti/on of said armor plate is adapted to rotate'as it moveswith said plug, said retaining groove being adapted to maintain saidarmor plate against removal even when the plug in front of said plate isdestroyed.

17. A cylinder lock comprising a cylinder of castA material, a key plugoi cast material for said cylinder and operating in a cast bore therein,a relatively non-corrosive lining `for said cylinder bore Ain which saidplug rotates, aligned tumbler chambers in said plug, sleeve andcylinder, said sleeve functioning as a spacer element between said plugand cylinder to prevent corrosive attraction of the two.

18. A cylinder lock comprising a cylinder of cast material having a plugbore, a key plug for said cylinder operating in said plug bore in saidcylinder, and a relatively non-corrosive sleeve lining for said plugbore arranged to separate the key plug from contact with the walls ofsaid bore.

19. A cylinder lock comprising a cylinder of cast material having a plugbore, a key plug for said cylinder operating in said plug bore in saidcylinder,'and a relatively non-corrosive sleeve arranged to separate thekey plug from contact with the walls of said bore.

20. A cylinder lock comprising a cylinder of cast material havinga plugbore, a key plug for said cylinder operating in a plug bore in saidcylinder, a relatively non-corrosive sleeve arranged to separate the keyplug from contact with the walls of said bore, and aligned tumblerchambers in said plug, sleeve, and cylinder.

21. A cylinder lock comprising a cylinder of cast material having a plugbore, a key plug for said cylinder operating in a plug bore in saidcylinder, a relatively non-corrosive sleeve arranged to separate the keyplug from contact with the walls of said bore, aligned tumbler chambersin said plug, sleeve, and cylinder, and means for securing said `sleevein position to maintain its chambers always in proper alignmentrelatively to said plug and cylinder chambers.

22. In acylinder lock, acylinder having a driver containing portionterminating in an upper surface, a. key plug mounted to rotate in theusual plug bore in said cylinder, said plug having a cutaway section,said cylinder having an opening in the plane of said cutaway sectionleading from the upper surface of the driver containing por- -tiondownwardly into the plug bore, and an armor plate insertible throughsaid opening and into said cutaway portion of the plug.

23. In a cylinder lock, a cylinder having a driver containing portionterminating in an upper surface, a key plug mounted to rotate in theusual plug bore in said cylinder, said plug having a cutaway section,said cylinder having an opening in the plane of said cutaway sectionleading from the upper surface of the driver containing portiondownwardly into the plug bore, an armor plate insertible through saidopening and into said cutaway portion of the plug, and a portion of saidarmor plate being adapted to remain in the cyl,- inder.

24. In a cylinder lock, a cylinder, a key plug mounted to rotate in theusual plug bore in said cylinder, said plug having a cutaway section,said cylinder having an opening in the plane of said cutaway sectionleading from the outside thereof to the plug bore, an armor plateinsertible into the cylinder through said opening and having portionsthereof lying in the cutaway section of the plug and in the cylinder,and a further armor plate inserted through said opening and adapted toprevent outward movement of said rst armor plate while serving also toprotect the cylinder.

MAXWELL C. MAXWELL. FRANK E. THOMPSON.- CHARLES LEDIN. CHARLES B. LOWE.

